I have a pair of 2600 series boxes that I keep in my home lab. Bought through eBay, both have a 12.2 version of code and seem to be working just fine for cert exercises. They are also equipped with WIC-1DSU-T1 modules (not V2) that I connect back to back with a crossover Telco cable. I configured both interfaces with the service-module t1 commands to set line coding, framing, data coding, clock source, line buildout and channelling then brought up both interfaces. I get the usual interface change and status messages that show both sides of the link are up, I can ping in both directions, pass traffic across the routers and life is good.

However, when I go back to examine the configs in both 2600s, only certain lines of the config are shown. Whether I look at the running or startup config, I get the same results. I do a reload, clear out all the counters, the routers come up with good links, I'm passing traffic, but still nothing in the configs for the interface s0/0 sections except for IP address and clock source. When I show the service-module status in priv mode, they look OK with the config settings I used. What I don't understand is why do I not see the config entries I made for the T1 interfaces. I know they're taking because if I change any of them to be different from the other, the link goes down until I again put the proper ones back in. I've run diags, numerous clears and anything else I can think of to show the status and behavior of the interfaces and they come up good every time. The only thing that looks hokey is the loss of the config statements. Even when I type them in and immediately afterward type a "do show running" command are those lines not shown. Can anybody shed some light on this for me? Thanks.